1. Field of the Invention
This invention relates to a hydraulic device such as the slant plate type hydraulic motor and hydraulic pump and, more particularly, to a hydraulic device which comprises: a cylinder rotatably supported in a frame; a plurality of plungers slidably fitted into the cylinder and arranged in a circle around the rotating axis of the cylinder; a slant plate held in the holder so as to be rotatable with respect to the cylinder; and a plurality of shoes which are mounted universally rotatably to the outer end of the plungers and which are placed in sliding contact with the inclined surface of the slant plate. The plungers are reciprocated in a sliding manner on the slant plate by the rotation of the cylinder or the cylinder is rotated by reciprocating the plungers slidably on the slant plate.
2. Description of the Prior Art
In hydraulic devices of the above type, shoes are placed in sliding contact with the inclined surface of the slant plate to make smooth the movement of the plungers along the slant plate. However, when the thrust of the plunger is suddenly reduced due to an oil pressure variation in the cylinder, the shoes may sometimes float from the inclined surface of the slant plate or vibrate. These phenomena in turn cause wear on the vibrating surface of the shoes and slant plate, noise and reduction in efficiency. The conventional practice to prevent the above phenomena is to place a common seat plate on the back of the shoes and secure the press plate which opposes the back of the seat plate to the slant plate holder. It is, however, very difficult from the standpoint of machining accuracy to keep the shoes, the seat plate and the press plate in an adequate pressing relationship with each other. Therefore, it is not easy to prevent the shoes from floating from the slant plate.